why were commuter rail lines that were powered by electricity an improvement over earlier forms of commuter rail lines

They were cleaner because they didn't burn fossil fuels.

Clean, quiet, no fireman shoveling coal, no smoke in the window if you open it. Starts in the morning without lighting fire ......

Thank you!

Well, the coal was back at the electric plant in Everett stinking up that neighborhood :)

Commuter rail lines that were powered by electricity offered several improvements over earlier forms of commuter rail lines. Here's why:

1. Efficiency: Electrically powered commuter rail lines were more energy-efficient compared to earlier steam-powered trains. Electric trains required less fuel consumption, resulting in reduced operating costs and environmental impact.

2. Speed and Acceleration: Electric trains could achieve higher speeds and faster acceleration compared to steam-powered trains. This allowed for quicker travel times, making them more attractive for commuters.

3. Reliability: Electricity provided a more reliable source of power compared to steam, which relied on a constant supply of water and fuel. Electric trains were less prone to breakdowns and operational disruptions, leading to improved service reliability.

4. Quiet and Clean: Electric trains produced less noise and smoke pollution compared to steam locomotives. This made for a more pleasant and comfortable commuting experience for passengers, while also reducing pollution levels in urban areas.

To find more specific information about this topic, you can refer to historical records or articles about the development and evolution of commuter rail lines. Additionally, books or online resources on the history of transportation or rail systems might also provide valuable insights into the advantages of electrically powered commuter rail lines over earlier forms.